1. Field of the Invention
This invention relates to a torque limiting clutch of the type described in our published U.K. Specification Nos. 1,517,692 and 1,517,693 namely a clutch of the type comprising opposed first and second members mounted for relative rotational and axial movement, a third member positioned between and mounted for rotational movement relative to the first and second members and for axial movement relative to at least one of the first and second members, the third member being provided with a torque transmitting element receiving aperture, a torque transmitting rolling element being positioned in the aperture in the third member, the first member comprising a driven member and being provided with a torque transmitting abutment for torque transmitting engagement with said torque transmitting element, another of said members comprising a driving member and being provided with a torque transmitting abutment for torque transmitting engagement with said torque transmitting element, resilient loading means to bias resiliently the first and second members towards one another, the arrangement being such that when the clutch is transmitting torque, the torque transmitting element is engaged with a driving member abutment and a driven member abutment so as thereby to prevent relative rotation between the driving and driven members and so that, on the torque to be transmitted exceeding a predetermined value, the torque transmitting element disengages from the abutment of at least one of the driving and driven members to permit of the driving and driven members to rotate relative to one another, a spacer element received in an opening in the third member and positioned between a first track axially located relative to one of the first and second members and a second track axially located relative to another one of the first and second members, a spacer element receiving means provided on at least one of the tracks and of such dimensions as to maintain the spacer element out of pressure contact with the tracks during torque transmission so as to ensure the torque transmitting element is maintained in pressure contact with the driven and second members, and a torque transmitting element receiving means provided on one of said driven and second members, whereby on disengagement of the torque transmitting element from the torque transmitting abutment on the driven member the third member is caused to rotate relative to the driven member and hence cause circumferential movement of the spacer element out of the spacer element receiving means and subsequently to cause the torque transmitting element to be engaged and maintained within the torque transmitting element receiving means with the driven and second members spaced apart by the spacer elements, the torque transmitting element receiving means being of such dimensions that the torque transmitting element is maintained out of pressure engagement with the driven and second members and relative rotation between the driving and driven members is permitted when the torque transmitting element is engaged in the torque transmitting element receiving means.
The present invention is concerned with an overload clutch of the above type in a version which comprises a driving part, a driven part, a cage guided rolling element, biasing means to bias axially said element into torque transmitting engagement with said parts when the clutch is engaged, a recess in one of said parts to accommodate said element and a spacer, movable by the cage into spacing relationship with said parts, to relieve the rolling element from said axial bias, as a result of relative rotation between the cage and said one part caused by orbital movement of the element when the clutch disengages, as a result of relative rotation between said parts; the rolling element being moved out of the recess into torque transmitting emgagement with said parts on resetting of the clutch by means of the cage, the cage and said other part being provided with interengageable resetting abutments to connect the cage to said other part on relative rotation between the cage and said other part whereby the rolling element is located in a torque transmitting position relative to the other part and thereafter relative rotation between the other part and the cage together on the one hand and said one part on the other hand, moving said one part into torque transmitting location with the element. Such a clutch will be referred to hereinafter as "of the type described".
2. Brief Description of the Prior Art
In our said published Specifications there are described a number of methods of resetting the clutches described therein which require either manual intervention or, in the case of automatic resetting, there is possible only resetting after the clutch has disengaged in a predetermined direction.